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A couple of B7971 board questions

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  • tkennedyny
    I looked for answers in the files section, but didn t see the info. So I m posting here. First, the assembly instructions say to see Figure 2 for a list of
    Message 1 of 7 , Apr 27, 2008
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      I looked for answers in the files section, but didn't see the info. So
      I'm posting here.

      First, the assembly instructions say to see Figure 2 for a list of
      resistor values for various HV supply voltages, but there's no Figure 2
      in the document (just 1 and 3). Does anyone know the value for a 180V
      supply?

      Second, I'd like to use the preferred connectors for the boards. Onno's
      site says "including high quality AMP connectors" when purchasing an
      assembled board. As I just bought bare boards, what connector are
      people using (for both the board and the mating cable end)?
    • Brett Paulin
      I just finished building my Smartsockets and got them fired up yesterday - :) Wow, B7971 s are *big*.. I just used a link for R31, since I m running at 170v.
      Message 2 of 7 , Apr 27, 2008
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        I just finished building my Smartsockets and got them fired up yesterday - :)
        Wow, B7971's are *big*..

        I just used a link for R31, since I'm running at 170v.

        If your power supply is not adjustable, then the accurate way would be to
        meter the current and choose a resistor accordingly, although I dont
        quite "get it" as to how a single anode resistor can be accurate if an
        unknown number of cathodes are illuminating.

        AMP is a brand of connectors.. there are many different styles in their range.
        I just used the ones my local electronics shop had, which are a bit tedious
        to assemble since each pin requires seperate crimping and insertion into the
        block.

        They had another style that worked with Ribbon cable and a little tool
        to "punch-down" the wires into the top of the connector (an IDC - insulation
        displacement connector), but they didnt have any of the appropriate punch
        tools in stock, so I couldnt use them.. after spending hours making the 36+
        crimp connections, I'd choose the quicker-to-assemble IDC models and get the
        tool next time unless you are only making a few sockets.

        Now to figure out Pythons string-slicing capabilities to write some funky
        display programs for them.. I've got as far as scrolling "Testing" back and
        forwards - :)

        regrds

        Brett

        On Mon, 28 Apr 2008 01:34:58 pm tkennedyny wrote:
        > I looked for answers in the files section, but didn't see the info. So
        > I'm posting here.
        >
        > First, the assembly instructions say to see Figure 2 for a list of
        > resistor values for various HV supply voltages, but there's no Figure 2
        > in the document (just 1 and 3). Does anyone know the value for a 180V
        > supply?
        >
        > Second, I'd like to use the preferred connectors for the boards. Onno's
        > site says "including high quality AMP connectors" when purchasing an
        > assembled board. As I just bought bare boards, what connector are
        > people using (for both the board and the mating cable end)?
      • Ray Fenwick
        Hi there. Do any of you guys fancy posting some pictures? I fancy a kit myself... Many thanks Ray
        Message 3 of 7 , Apr 28, 2008
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          Hi there.

          Do any of you guys fancy posting some pictures? I fancy a kit myself...

          Many thanks

          Ray

          On 28 Apr 2008, at 04:57, Brett Paulin wrote:

          > I just finished building my Smartsockets and got them fired up
          > yesterday - :)
          > Wow, B7971's are *big*..
        • Quixotic Nixotic
          ... Well Ray, the boards do what they say they will do. They are good! I used crimp connectors from D sockets for my tubes, soldered to the smartsocket PCBs.
          Message 4 of 7 , Apr 28, 2008
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            On 28 Apr 2008, at 10:35, Ray Fenwick wrote:

            > Hi there.
            >
            > Do any of you guys fancy posting some pictures? I fancy a kit
            > myself...
            >
            > Many thanks
            >
            > Ray
            >

            Well Ray, the boards do what they say they will do. They are good! I
            used crimp connectors from D sockets for my tubes, soldered to the
            smartsocket PCBs. They worked just fine.

            I just uploaded my files for my clock to the files section, in a
            folder called John's clock. Pictures of the built unit are in the
            pictures section.

            I have uploaded:

            1] My very simple circuit diagram. I knocked it up in no time on
            Veroboard. It's up to you how you generate your high voltage for the
            tubes. I used the back-to-back twin transformer method.

            2] A list of four letter words to burn to i2C EEPROM - a 24AA512.
            This is a list of all the allowable English four letter words in the
            board game of 'Scrabble'. No I haven't heard of a lot of them either.
            3,539 four letter words in total. Yes the rude ones are all in there.
            There is no profanity setting, just switch the clock off when the
            prurient are visiting. My sister is an ordained minister and so far
            it has failed to say anything abusive in her presence, thank dog. At
            other times it has been hilarious when it says something seemingly
            appropriate...

            3] PicBasic code for the clock (there are some comments in there of
            how it works)

            4] Hex code to burn a 16F628a PIC for the clock.

            If anyone wants to build this clock, I can supply a burned PIC and
            EEPROM set.

            The clock is not 100% as I would like it and I keep meaning to
            revisit it and tidy up the editing etc., and add some UDCs (user
            defined characters) and animations, which is why I haven't posted my
            gubbins before. When I do this I will upload new code and make it
            available.

            In operation the clock tells the time every minute for a while. The
            rest of the time it is displaying random 4 letter words. The fade
            effect changes every now and again. I can't remember just when, but
            look in the PicBasic code and you can probably work it out.

            Best wishes,

            John S
          • Brett Paulin
            ... OK, You asked for it.. Family Photo :) - I hope noone minds attachments on the mailing list - B7971 s in Smartsockets, IN4, IN8, IN12 in
            Message 5 of 7 , Apr 28, 2008
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              > Do any of you guys fancy posting some pictures?
              > I fancy a kit myself... Many thanks
              > Ray

              OK, You asked for it.. Family Photo :) - I hope noone minds attachments on
              the mailing list

              - B7971's in Smartsockets, IN4, IN8, IN12 in SmartNixie-Socket, IN13 Tube

              Sorry about the low-res, its a camera-phone. I'll make some better ones when
              they get nice cases to live in and are worth photographing :)

              Kits arent usually worth it for low volume producers - Smartsockets arent too
              hard to source the parts for yourself - Building them took more time than
              finding the parts.

              Onno has the Micros, PCB, Sockets and Tubes available here
              http://www.tromop.eu/cms/index.php?option=com_content&task=view&id=24&Itemid=40
              which just leaves you the resistors, transistors and connectors to find.

              My Liquid Neon Tubes arrived today, wait till you see what I have in mind for
              the next Smartsocket ! :)

              regards

              Brett
            • Onno
              Terry, The connectors and headers i m using right now came from Farnell. Header: 9731636 MOLEX 22-05-7058 Connect: 146256 MOLEX
              Message 6 of 7 , Apr 28, 2008
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                Terry,

                The connectors and headers i'm using right now came from Farnell.

                Header: 9731636 MOLEX 22-05-7058
                Connect: 146256 MOLEX 22-01-2055
                Pins: 9773789 MOLEX 08-50-0032

                Grtx,
                Onno
              • Chris
                ... yesterday - :) ... be to ... dont ... an ... Hello, If the datasheet for the B7971 s is to believed then the different lengths of the cathodes lend
                Message 7 of 7 , Apr 29, 2008
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                  --- In smartsockets@yahoogroups.com, Brett Paulin <yahoogroups@...>
                  wrote:
                  >
                  > I just finished building my Smartsockets and got them fired up
                  yesterday - :)
                  > Wow, B7971's are *big*..
                  >
                  > I just used a link for R31, since I'm running at 170v.
                  >
                  > If your power supply is not adjustable, then the accurate way would
                  be to
                  > meter the current and choose a resistor accordingly, although I
                  dont
                  > quite "get it" as to how a single anode resistor can be accurate if
                  an
                  > unknown number of cathodes are illuminating.



                  Hello,
                  If the datasheet for the B7971's is to believed then the different
                  lengths of the cathodes lend themselves very well to approporiately
                  chosen resistors in the standard values series.

                  Not sure if that was the intention or if that's how it worked out,
                  but to clarify , you should choose the resistor value for the cathode
                  resistors to get you as close as possible to the desired current
                  values for your device , ZM1350 or B7971. However you may be slightly
                  out even then , and the voltage from the supply a little high still,
                  in which case adding a small amount of anode resistance, used just to
                  trim the final voltage, can be used. It was probably overkill on my
                  part to include it, but I felt that for all the time and effort it
                  takes to be able to quickly add a bit of resitance or possibly even a
                  fuse it was worth including.

                  In a test I did with a 200V supply I found that when comparing one
                  tube with the the resistors for 170V plus a small anode resitor,
                  against a tube with reistors for 200V and no anode resitor, there was
                  only a very slight difference in the apparent brightness of the
                  cathodes regardless of the number which were being actived. Flat
                  orange is a difficult colour to judge brightness of and radiant
                  orange is very difficult to judge in close relative terms.

                  Basically what I wanted to say was that the anode reistor is moreof a
                  luxury and for added protection. A small reduction in cathode current
                  can create a much longer tube lifetime in the right circumstances and
                  so I opted to have one, just in case anyone needed to set the
                  voltages from a non-adjustable supply which demand odd valued
                  resistors.

                  As long as the bulk of the current limiting is being done with the
                  cathode resistors any anode resistance you need to choose to further
                  limit the current for one cathode will not produce a very noticeable
                  effect when all cathodes are activated


                  Chris
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